Pressure testing a fuel tank

gw204 · #1 12-31-2003, 11:29 AM

Can anyone tell me the proper procedure for pressure testing a fuel tank?

Thanks.

Rusty Bucket · #2 01-01-2004, 03:20 AM

I'm not sure how "proper" the procedure was, but I pressure tested the 45gal. alum. tank out of an old Angler hull years ago. I used a short section of bike innertube with the valve stem on it, some hose clamps, a cheap pressure guage and some fuel line. I sealed the fill tube with the innertube section, hose clamps and a PVC pipe plug. I put the pressure guage in a piece of fuel hose clamped onto the fuel supply tube. I plugged the vent with a piece of fuel hose with a bolt stuck in it. It held 25lbs. of air all night and I pronunced it seaworthy. BUT... I didn't bed it down right and it wore holes in the hull......the hull leaked, but the tank didn't. I tested the hull with a garden hose on the trailer in the yard. Peed two streams amidships right where the front corners of the tank bore on the inside of the hull.

[ January 01, 2004, 02:22 AM: Message edited by: Rusty Bucket ]

lost2a6 · #3 01-01-2004, 02:01 PM

When I had a tank built they pressured it up to about 3-4 psi and then went over all of the welds with soapy water.

David Bienvenu · #4 01-03-2004, 06:41 PM

I own an industrial radiator and heat exchanger shop. Pressure testing is something we do every day. We hydrotest to 750 PSI.

Be very careful pressure testing a tank with air. Depending on the construction materials of the tank and the size it may not be safe to go above 5-10 psi. PSI is pounds per square inch. The more surface area a tank has the more pressure applied to the walls. We would consider it dangerous to put 25 PSI of air in an empty square or rectangular 1/8" aluminum welded tank. Filled with water and using a hand operated pump (Like plumbers use)you can go higher. The fact is that water won't compress and if the tank splits open worst that will happen is you get wet.

As shared above, 5 psi air and a spray bottle of dish washing soap and water will do the trick. (409, windex etc. won't "hang in there")However remember that if the tank is not empty you will only find air leaks above the fuel level line.

Rusty Bucket · #5 01-04-2004, 03:00 AM

David, why didn't you warn me before I pressured that cruddy looking old tank? [img]images/icons/smile.gif[/img] Add that to a long list of stuff I've done because I wasn't thinking or didn't know any better(or both). Maybe the $3 gauge saved me. I'd even plastered some little corroded places on top of the tank with Marine Tex because it leaked air the first time I pressured it.

PipeDreamsMarine · #6 01-06-2004, 08:17 AM

5 pounds max Brian, then soap all of the seams and fittings..

gw204 · #7 01-06-2004, 09:08 AM

Thanks guys. I thought it was a low number like 5 psi but just wanted to make sure.

I'm not going to bother w/ the soap and water trick, other than around the sending unit. If the pressure test reveals any leaks whatsoever, I'm going to replace the tanks. After all, it's 19 years old. [img]images/icons/smile.gif[/img]

Thanks again.